C4+ does not exist but Pb4+ exists although both belong to the same group. This is because
I. size of carbon is much smaller than Pb. II. large amount of energy is needed in case of carbon.
III. of inert pair effect.
IV. nucleus cannot hold such a large number of electrons.
The correct statement(s) is/are
As you go down a group, the size of the atom increases and the ionization enthalpy decreases due to the shielding of outermost electrons by the inner electrons.